Add patches to remove the unused optional dependencies tracked in tree

Also performs the usual `cargo update`.

patches/ethereum/libsecp256k1/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "libsecp256k1"
+version = "0.7.99"
+description = "Patch to an empty crate"
+license = "MIT"
+repository = "https://github.com/serai-dex/serai/tree/develop/patches/ethereum/libsecp256k1"
+authors = ["Luke Parker <lukeparker5132@gmail.com>"]
+keywords = []
+edition = "2021"
+
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+
+[features]
+std = []
+static-context = []

patches/ethereum/libsecp256k1/src/lib.rs

@@ -0,0 +1 @@
+const _NEVER_COMPILED: [(); 0 - 1] = [(); 0 - 1];